Wellbore debris cleanup tools have in the past focused on maintaining debris laden fluid flow velocity into the tool body through a narrow inlet pipe. At the top of the inlet pipe the diameter grew and the velocity slowed and the intent was for the larger debris to fall into a surrounding annular space around the inlet pipe. The top of the inlet pipe has a cone shaped cover spaced from the pipe end to act as an incoming flow diverter so that the debris would be over the annularly shaped connection volume while the remaining incoming flow with some finer debris would be drawn through a screen and then mixed with motive fluid for the educator that drew the intake flow into the housing. This basic tool is offered by Baker Hughes Incorporated of Houston, Tex. USA under the name VACS®. This patent again illustrates a small centrally located inlet pipe 100 in FIG. 8 designed to maintain flow velocity for solids entrainment. Similar designs from the same source are U.S. Pat. Nos. 8,960,282; 6,176,311 and 7,478,687. One adaptation of this design is shown in U.S. Pat. No. 8,607,857 where there is an articulated pickup tube to reach into recesses in a blowout preventer.
While these designs function well enough in generally vertical applications there are other instances where there are long horizontal runs where debris, mainly sand, amasses and can cause the well flow to decline. Those skilled in the art have used coiled tubing but have struggled to get the debris laden fluid back to surface on low pressure wells. The option of using foamed fluids or concentric coiled tubing to get the debris to surface is expensive and requires special equipment and expertise. The present invention addresses such a situation with a long tail pipe on a vacuum cleanup tool that incorporates a bottom shoe featuring a one way valve to hold the contained sand from coming out of the tailpipe when circulation stops to add additional string above the cleanup tool so that the tailpipe can advance further into the horizontal run that has filled with sand. The one way valve can be a flapper valve or an assembly of spring loaded fingers that get pulled back and out of the way with circulation. The tail pipe progresses into the horizontal run and captures the sand or other debris inside with the aid of the one way valve fingers. Borehole as used herein refers to a wellbore extending to a subterranean location, for example.
These and other aspects of the present invention will be more readily apparent to those skilled in the art after a review of the detailed description of the preferred embodiment and the associated drawing while recognizing that the full scope of the invention is to be determined by the appended claims.